This invention relates to a storage system.
In recent years, information has been increasing in interest more and more because of, for example, generalization of big data analysis; disaster recovery for protecting important information has also been increasing in importance. In the disaster recovery technology, US 2009/0271582 A discloses a technique that, in normal operations, controls reads/writes from a host computer so as to access only a storage apparatus in a main site and copies data to a storage apparatus in a remote site, and upon occurrence of a failure in the main site, switches the accesses to the remote site.